1. Field of the Invention
The present invention relates to a vacuum cleaner. More particularly, the present invention relates to a multi-cyclone dust collector for a vacuum cleaner that separates and collects contaminants from sucked air by centrifugal force.
2. Description of the Related Art
A cyclone type vacuum cleaner, which separates contaminants from sucked air by centrifugal force, employs a cyclone dust collector providing semi permanent use. Because a cyclone type vacuum cleaner is more sanitary and convenient than a vacuum cleaner employing a dust bag or a dust filter, cyclone type vacuum cleaners have become widespread.
An example of a conventional cyclone dust collector is shown in FIG. 1. Referring to FIG. 1, the conventional cyclone dust collector 500 includes a cylindrical cyclone body 510 in which sucked air containing contaminants forms a whirling current therein, an air inlet 520 through which the air containing contaminants enters, and an air outlet 530 through which clean air is discharged. The air inlet 520 is disposed at a side of an upper portion of the cyclone body 510 in a tangential direction relative to the cyclone body 510 so that the air entering the cyclone body 510 whirls downward easily. The air outlet 530 is disposed at a center of a top surface of the cyclone body 510 so that the air, which has contaminants removed as the air whirls downwardly, then rises up inside the cyclone body 510, and is discharged out of the cyclone dust collector 500. Separated contaminants are discharged in the gravity direction through a contaminants outlet 540 that is formed at a lower portion of the cyclone body 510.
However, in the conventional cyclone dust collector 500, the air whirling downwardly collides with the air rising up inside the cyclone body 510 because both the air inlet 520 and the air outlet 530 are disposed at the upper portion of the cyclone body 510. Accordingly, the conventional cyclone dust collector 500 has a problem that a dust collecting efficiency thereof is decreased due to collision between the rising air and the descending air.
Currently, a multi-cyclone dust collector has been developed and has become widespread. The multi-cyclone dust collector separates contaminants from air in two or more stages, and especially provides a plurality of cyclones for separating fine contaminants. An example of a conventional multi-cyclone dust collector 600 is shown in FIG. 2.
Referring to FIG. 2, the conventional multi-cyclone dust collector 600 includes a first cyclone 610 that centrifugally separates contaminants from sucked air, and a plurality of second cyclones 620 that sucks the air being discharged from the first cyclone 610, and then, separates fine contaminants remaining in the air. First and second air inlets 611 and 621 through which air is sucked into the first and second cyclone 610 and 620, and first and second air outlets 612 and 622 through which air having contaminants removed is discharged are disposed at upper portions of the first and second cyclones 610 and 620. Accordingly, air having contaminants removed is discharged in a direction opposite to the gravity direction. Also, first and second dust receptacles 613 and 623 are formed under the first and second cyclones 610 and 620. Therefore, contaminants that are separated in the first and second cyclones 610 and 620 are discharged in the gravity direction, and then are collected in the first and second receptacles 613 and 623, respectively.
Because the first and second receptacles 613 and 623 are not isolated from the first and second cyclones 610 and 620 in which air forms whirling currents, contaminants that are collected in the first and second receptacles 613 and 623 are re-scattered and flow back due to the whirling current. The backflow of contaminants decreases the dust collecting efficiency of the cyclone dust collector 600 and shortens the filter maintenance cycle of the cyclone dust collector 600.
Furthermore, the multi-cyclone dust collector 600 still has the problem that air collision occurs so as to decrease the dust collecting efficiency as described above, because the air inlets 611 and 621 and the air outlets 612 and 622 are disposed at the upper portions of the first and second cyclones 610 and 620.
Furthermore, the conventional multi-cyclone dust collector 600 has a drawback that the height thereof is high, because the space in which the air whirls and the space in which contaminants are collected are arranged vertically.
Accordingly, there is a need for an improved multi-cyclone dust collector the height of which is lower and is more compact as compared of the conventional multi-cyclone dust collector.